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El mecanismo de activación de la ubiquitina revelado por la estructura de un complejo MoeB-MoaD bacteriano

M W Lake¹, M M Wuebbens, K V Rajagopalan

¹Department of Biochemistry and Center for Structural Biology, State University of New York at Stony Brook, Stony Brook, New York 11794-5115, USA.

|November 20, 2001

Resumen

Los investigadores descubrieron similitudes estructurales entre las proteínas de biosíntesis del cofactor de molibdeno bacteriano (MoeB y MoaD) y las enzimas humanas activadoras de la ubiquitina (E1). Este hallazgo sugiere un origen evolutivo compartido y proporciona información sobre las vías de modificación de proteínas.

Área de la Ciencia:

La bioquímica es la bioquímica.
Biología Estructural Biología estructural.
Biología evolutiva Biología evolutiva.

Sus antecedentes:

La ubiquitina y los modificadores de proteínas relacionados se activan por las enzimas E1 utilizando ATP.
La biosíntesis del cofactor de molibdeno (Moco) involucra las proteínas de Escherichia coli MoeB y MoaD.
Las enzimas MoeB y E1 catalizan reacciones mecánicamente similares.

Objetivo del estudio:

Para presentar las estructuras cristalinas del complejo MoeB-MoaD.
Para aclarar las similitudes funcionales entre los sistemas MoeB/MoaD y E1/ubiquitin.
Proporcionar un marco molecular para la comprensión de la activación de proteínas y la incorporación de azufre.

Principales métodos:

Cristalografía de rayos X del complejo MoeB-MoaD (formas apo, ligadas al ATP y adenilato de MoaD).

Principales resultados:

Se destacaron las similitudes estructurales y mecánicas entre los sistemas MoeB-MoaD y E1-ubiquitin.
MoaD comparte un pliegue conservado y un motivo Gly-Gly con ubiquitin.
MoeB activa MoaD a través de un intermediario acilo-adenilato, similar a las enzimas E1.

Conclusiones:

La ubiquitina y las enzimas E1 probablemente evolucionaron de genes ancestrales relacionados con moaD y moeB.
Las ideas estructurales sobre el complejo MoeB-MoaD ayudan a comprender la ubiquitina, Rub, la activación de SUMO y la biosíntesis de Moco / tiamina.

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